DB2 Query Patroller Administration Guide

Operation

You can perform DB2 Query Patroller operations through a combination of the command-line interface and QueryAdministrator. This chapter provides information about the following operations:

• Starting and Stopping DB2 Query Patroller.

• Controlling Job Flow and Execution.

• Releasing and Canceling Jobs.

• Monitoring the System.

• The Control Program (iwm).

It also provides control program, command syntax, and parameter descriptions.

Starting and Stopping DB2 Query Patroller

The control program (iwm) starts and stops DB2 Query Patroller. When starting DB2 Query Patroller, you should start the server node first, followed by the agent nodes. When stopping DB2 Query Patroller, you should stop the agent nodes first, followed by the server node. You must run iwm on each node for these activities to occur.

You can use a number of methods to pause DB2 Query Patroller without fully stopping the system. For instance, you can stop one or more of the agent nodes using the iwm program or QueryAdministrator. You can also make one or more nodes quiescent using the command-line interface or the QueryAdministrator and then later reactivate the node. You can alter the system or data source parameters to prevent additional jobs from being scheduled or even alter the data source status to prevent new jobs from being submitted.

Controlling Job Flow and Execution

You can control the number of jobs, where they run, and the load put on the database by altering the system, data source, and job queue parameters. See Parameters for parameter descriptions.

Releasing and Canceling Jobs

If a user submits a query to DB2 Query Patroller and DB2 Query Patroller estimates the job's cost to be greater than the user's limit, then the job receives a hold status. In order for a job with a hold status to run, the system administrator must release the job using QueryAdministrator or the command-line interface. While a job is in the DB2 Query Patroller system, either the system administrator or the job's owner may cancel the job. A list of the jobs with a hold status or those jobs with some other status can be obtained through the command-line interface or QueryMonitor. See the DB2 Query Patroller User's Guide for more information about viewing a job's status.

Monitoring the System

In addition to monitoring job flow, the status of DB2 Query Patroller, and the database software, you need to monitor the host system itself. You can use the command-line interface to perform some monitoring and automated operations by using shell scripts, tools such as awk, and languages such as Perl. However, to be alerted to severe problems, monitor the system error log file produced by the server and agent components.

The Control Program (iwm)

The DB2 Query Patroller control program (iwm) starts, stops, and displays the status of DB2 Query Patroller processes. The following diagram provides the syntax for iwm:

>>-iwm----+-ps-----------------------------+-------------------><
          |        .-all----.              |
          +-start--+-server-+---+--------+-+
          |        '-agent--'   '-TRACE--' |
          |       .-all----.               |
          '-stop--+-server-+---------------'
                  '-agent--'
 

Table 3. iwm Parameter Descriptions

Parameter	Description
ps	This parameter displays a list of all DB2 Query Patroller processes running on this machine. The list displays in ps format. For an active agent node, you should see the iwm_net and iwm_nodemgr processes listed. You may also see other processes if the node has jobs running. For an active server node, you should see the iwm_net, iwm_server, iwm_remote, iwm_sched, and several iwm_local processes listed. If the log monitor is active, you should see the iwm_logmon process listed.
start {all | server | agent} [trace]	This parameter starts DB2 Query Patroller processes. The option defines the set of processes to start. The all option specifies that both the server and agent processes are to be started. The server option starts only the server processes. The agent option starts only the agent processes. Only one node per system should be started with the all or server options.
stop [ all | server | agent ]	This parameter directs DB2 Query Patroller to stop the requested DB2 Query Patroller process. If you do not specify any options, all is the default.

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